rustc-ap-rustc_error_codes 638.0.0

Automatically published version of the package `rustc_error_codes` in the rust-lang/rust repository from commit 30ca215b4e38b32aa7abdd635c5e2d56f5724494 The publishing script for this crate lives at: https://github.com/alexcrichton/rustc-auto-publish
Documentation 
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Something other than a type or an associated type was given.

Erroneous code example:

```compile_fail,E0575
enum Rick { Morty }

let _: <u8 as Rick>::Morty; // error!

trait Age {
    type Empire;
    fn Mythology() {}
}

impl Age for u8 {
    type Empire = u16;
}

let _: <u8 as Age>::Mythology; // error!
```

In both cases, we're declaring a variable (called `_`) and we're giving it a
type. However, `<u8 as Rick>::Morty` and `<u8 as Age>::Mythology` aren't types,
therefore the compiler throws an error.

`<u8 as Rick>::Morty` is an enum variant, you cannot use a variant as a type,
you have to use the enum directly:

```
enum Rick { Morty }

let _: Rick; // ok!
```

`<u8 as Age>::Mythology` is a trait method, which is definitely not a type.
However, the `Age` trait provides an associated type `Empire` which can be
used as a type:

```
trait Age {
    type Empire;
    fn Mythology() {}
}

impl Age for u8 {
    type Empire = u16;
}

let _: <u8 as Age>::Empire; // ok!
```